A rapid inoculation method for microalgae biofilm cultivation based on microalgae-microalgae co-flocculation and zeta-potential adjustment. (April 2019) - Zheng, Yaping
Graphical abstract: Highlights: MMC with zeta potential adjustment were effective way for biofilm inoculation. Long stripe A. falcatus acted as bond linking main microalgae and formed MMC. Optimal matching were S. obliquus and A. falcatus with the mixing ratio of 4–1. Inoculation time shorten from 4 h to 1.5 min by mixing opposite charge suspensions. Biofilm with this inoculation method grew to 229.15 g m −2 and increased by 90.15%. Abstract: Due to the small size, similar density to water, cells inoculating onto the solid carrier is a major challenge for microalgae biofilm cultivation. To reduce biofilm inoculation time, A. falcatus with long stripe were chosen as the bond linking with the main microalgae cells forming microalgae-microalgae co-flocculation by bridging and twining. The optimal matching species were S. obliquus and A. falcatus with the volume ratio of 4–1. By changing the zeta-potential of the microalgae-microalgae co-flocculation to positive and negative through pH regulating, the inoculation time was significantly shorted from 4 h to 1.5 min due to the charge neutralization. Fortunately, the added A. falcatus and pH regulation has no negative effects on biofilm growth. Inversely, the porous microstructure of microalgae-microalgae co-flocculation improve the transfer efficiency of nutrients, resulting a 90.15% increase on biomass productivity (229.15 g m −2 ) comparing to pure microalgae species.